A charge pump circuit is a type of switched capacitor circuit that may be used to convert a direct current (DC) input voltage to another DC voltage. A charge pump can be configured to generate an output voltage that is a multiple (e.g., 2, 3 . . . N times) the input voltage or it can set an output voltage that is a fraction thereof (e.g., ½, ⅓ . . . 1/N times of the input voltage). In some implementations, such circuit can also generate a negative output voltage from a positive input voltage. Since the charge pump circuit does not require inductors to do the voltage conversion, it is sometimes referred as an inductor-less DC/DC converter.
A shortcoming of existing direct current converters is that they may have a large inrush current in sensitive circuit elements, such as switching transistors.
Accordingly, what is needed is a design for a higher efficiency converter, without adding considerable cost and complexity, which can limit a current of the switching transistors.